Large inflatable exercise balls have been available to the public for quite some time, and are commonly used in fitness routines, such as those involving yoga or pilates. A user basically sits on the ball and stretches or exercises. Such exercise, however, generally requires a great degree of balance to prevent accidental injury caused by the ball rolling out from under the user. In addition, because the ball is not prevented from rolling or rotating, only a limited number of exercises can be done with such a ball, even by the experienced user.
Therefore, what is needed is an exercise apparatus that does not rotate or react with universal motion when forcibly contacted by an individual, but rather one that translates the these reaction forces imposed by the stretching and/or exercising individual into static frictional forces that automatically maintain the stability of the exercising individual.